Cervix dilation explanation

During the first stage of labour, contractions make your cervix gradually open up (dilate). This is usually the longest stage of labour. At the start of labour, the cervix starts to soften so it can open. This is called the latent phase. It can take many hours, or even days, before you’re in established labour.

Established labour is when your cervix has dilated to more than 3cm and regular contractions are opening the cervix.

Your cervix needs to open about 10cm for your baby to pass through. This is what’s called being fully dilated, and means that you've moved into the second stage of labour.